San Ysidro, California, United States

🇺🇸 San Ysidro is a district of the City of San Diego, immediately north of the U.S.-Mexico border. It neighbors Otay Mesa West to the north, Otay Mesa to the east, and Nestor and the Tijuana River Valley to the west; together these communities form South San Diego, a practical exclave of the City of San Diego. Major thoroughfares include Beyer Boulevard and San Ysidro Boulevard.

Border crossing San Ysidro is home to the fourth busiest land border crossing in the world. It is the second-busiest border crossing between two sovereign nations (after the Johor–Singapore Causeway) and the busiest border crossing in Western Hemisphere.

Statistics from the U.S. Department of Transportation state more than 15 million vehicles and 36.7 million people entered the United States at the San Ysidro Port of Entry in 2019. The great majority of these are workers (both of Mexican and U.S. nationality) commuting from Tijuana to jobs in the greater San Diego area and throughout southern California. There is also reverse traffic, both of workers traveling to maquiladoras in Mexico and those purchasing services or seeking entertainment in Tijuana. 2009 studies estimated that wait times for vehicles at the San Ysidro LPOE averaged 1.5 to 2 hours during the commuter peak period.

For pedestrians, in 2012, morning waits to enter the United States could last more than two hours — and twice that time during peak weekend periods. Roughly one-fifth of the 25,000 daily northbound crossers remained in San Ysidro to work, shop, visit family etc., according to the San Ysidro Chamber of Commerce. Many more boarded the San Diego Trolley or other public transportation to work, schools, stores, banks, medical appointments and family gatherings across San Diego County. In 2016 a second pedestrian crossing was opened, "PedWest", connecting Plaza Viva Tijuana via a walkway to the border next to the El Chaparral auto crossing, with Virginia Avenue in San Ysidro.

San Ysidro is also where ICE deports the most Mexicans back into Mexico; in 2003, this was 360,172 people.

Trucks cannot use the San Ysidro crossing and must use the Otay Mesa Port of Entry instead. An expansion of the San Ysidro Port of Entry is taking place in three parts and was scheduled to be completed in the spring of 2014. The $577 million project will expand and veer Interstate 5 to the west. Slated to be built are a new northbound inspection facility, including primary vehicle inspection booths, a secondary inspection area, an administration space, and a pedestrian-processing facility. A new southbound inspection facility is also planned.